Plasma welding - pilot arc

[MaroB]

Hi All,

I would like to ask You for help in solving a problem with not normal behavior of pilot arc on plasma welding machine.

Short description of the problem: the pilot arc is not stable and flickers. It happens in hard to be defined time and conditions: sometimes just after starting the arc, sometimes the arc is stable for few minutes and then starts to flicker or it happes after performing few welds.

The main parameters of pilot arc:
- pilot gas (argon) flow rate: 0,5-0,7 l/min (1,0-1,5CFH)
- current: 9-10 Amps

Anybody have some ideas what could cause that behavior?

Marek

 

[ledon]

When was the last time the machine was serviced? That type of inconsistancy normally happens when the contacts inside the machine/torch assembly are dirty.

 

[riccardo67]

Hi
usually is a problem of magnetism..

RIC

 

[MaroB]

Machines are serviced in a regular way, I also have to add that I have two different machines for plasma welding and this happened on both of them more or less in the same time.

Riccardo67, can You plese write something more about this magnetism? What can I chck and how to proove that this is the case?